Getting User Identity on my base Controller constr

问题:

I have a base Controller on my ASP.NET MVC4 website that have a Constructor simple as this:

public class BaseController : Controller
{
    protected MyClass Foo { get; set; }
    public BaseController()
    {
        if (User.Identity.IsAuthenticated))
        {
            Foo = new MyClass();
        }
    }
}

However I cannot access User here. It's null. But on my inherited Controllers it's fine.

Thanks

回答1:

Controller instantiation will occur before authorisation takes place. Even if your MVC application calls RenderAction() several times and you end up creating say, five different controllers, those five controllers will be created before any OnAuthorization takes place.

The best approach to deal with these situations is to use Action Filters. The Authorize Attribute is fired early and may well be suited to your situation.

First, let's create an AuthorizationFilter.

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class MyClassAuthorizationAttribute : Attribute, IAuthorizationFilter
{
    public void OnAuthorization(AuthorizationContext filterContext)
    {
        if (filterContext.HttpContext.User.Identity.IsAuthenticated)
        {
            filterContext.Controller.ViewData["MyClassInstance"] = new MyClass();
        }
    }
}

Now let's update our Controller

[MyClassAuthorization]
public class BaseController : Controller
{
    protected MyClass Foo
    {
        get { return (MyClass)ViewData["MyClassInstance"]; }
    }
}

回答2:

In this case I would override Controller Initialize method:

protected override void Initialize(RequestContext requestContext)
{
   base.Initialize(requestContext);
   // User.Identity is accessible here
}